|
alternate mark inversion (AMI)
|
Original method of formatting T1 and E1 data streams.
|
|
asymmetrical digital subscriber line (ADSL) interface
|
Physical WAN interface for connecting a Services Router to a digital subscriber
line access multiplexer (DSLAM). An ADSL interface allocates line bandwidth
asymmetrically with downstream (provider-to-customer) data rates of up to
9 Mbps and upstream (customer-to-provider) rates of up to 640 Kbps, depending
on the implementation.
|
|
Annex A
|
ITU-T Standard G.992.1 that defines how ADSL works over plain old telephone
lines (POTS).
|
|
Annex B
|
ITU-T Standard G.992.1 that defines how ADSL works over Integrated Services
Digital Network (ISDN).
|
|
binary 8-zero substitution (B8ZS)
|
Improved method of formatting T1 and E1 data streams, in which a special
code is substituted whenever 8 consecutive zeros are sent over the link.
|
|
Challenge Handshake Authentication Protocol (CHAP)
|
Protocol that authenticates remote users. CHAP is a server-driven, three-step
authentication method that depends on a shared secret password residing on
both the server and the client.
|
|
checksum
|
See frame checksum sequence.
|
|
channel service unit (CSU)
|
Unit that connects a digital telephone line to a multiplexer or other
signal service.
|
|
Cisco HDLC
|
Cisco High-level Data Link Control protocol. Proprietary Cisco encapsulation
for transmitting LAN protocols over a WAN. HDLC specifies a data encapsulation
method on synchronous serial links by means of frame characters and checksums.
Cisco HDLC enables the transmission of multiple protocols.
|
|
clock source
|
Source of the consistent, periodic signal used by a router to synchronize
data communication and processing tasks.
|
|
CSU compatibility mode
|
Subrate on a T3 interface that allows a Services Router to connect with
a channel service unit (CSU) with proprietary multiplexing at the remote end
of the line. Subrating a T3 interface reduces the maximum allowable peak rate
by limiting the payload encapsulated by the High-level Data Link Control protocol
(HDLC).
|
|
data-link connection identifier (DLCI)
|
Identifier for a Frame Relay virtual connection, also called a logical
interface.
|
|
data service unit (DSU)
|
Unit that connects a data terminal equipment (DTE) device—in this
case, a Services Router—to a digital telephone line.
|
|
data terminal equipment (DTE)
|
RS-232 interface that a Services Router uses to exchange information
with a serial device.
|
|
DS1
|
Digital signal 1, another name for a T1 interface.
|
|
DS3 interface
|
Digital signal 3, another name for a T3 interface.
|
|
data inversion
|
Transmission of all data bits in the data stream so that zeros are transmitted
as ones and ones are transmitted as zeros. Data inversion is normally used
only in alternate mark inversion (AMI) mode to guarantee ones density in the
transmitted stream.
|
|
E1 interface
|
Physical WAN interface for transmitting signals in European digital
transmission (E1) format. The E1 signal format carries information at a rate
of 2.048 Mbps and can carry 32 channels of 64 Kbps each.
|
|
encapsulation type
|
Type of protocol header in which data is wrapped for transmission.
|
|
Fast Ethernet interface
|
Physical LAN interface for transmitting data at 100 Mbps. Fast Ethernet,
also called 100Base-T, additionally supports standard 10Base-T Ethernet transmission.
|
|
Flexible PIM Concentrator (FPC)
|
Logical identifier for a Physical Interface Module (PIM) installed on
a Services Router.
|
|
frame check sequence (FCS)
|
Calculation that is added to a frame to control errors in High-level
Data Link Control (HDLC), Frame Relay, and other data link layer protocols.
|
|
Frame Relay
|
An efficient WAN protocol that does not require explicit acknowledgement
of each frame of data. Frame Relay allows private networks to reduce costs
by sharing facilities between the end-point switches of a network managed
by a Frame Relay service provider. Individual data link connection identifiers
(DLCIs) are assigned to ensure that customers receive only their own traffic.
|
|
fractional E1
|
Service also called channelized E1, in which a 2.048-Mbps E1 link is
subdivided into 32 DS0 time slots (channels) in which time slot 0 is reserved.
The individual channels or groups of channels connect to different destinations,
and customers pay for only the channels used and not for the entire line.
|
|
fractional T1
|
Service also called channelized T1, in which a 1.544-Mbps T1 link is
subdivided into 24 DS0 time slots (channels) in which time slot 0 is reserved.
The individual channels or groups of channels connect to different destinations,
and customers pay for only the channels used and not for the entire line.
|
|
High-level Data Link Control
|
International Telecommunication Union (ITU) standard for a bit-oriented
data link layer protocol on which most other bit-oriented protocols are based.
|
|
hostname
|
Name assigned to the Services Router during initial configuration.
|
|
ITU-T G.992.1 Standard
|
International Telecommunications Union standard that requires the downstream
(provider-to-customer) data transmission to consist of full-duplex low-speed
bearer channels and simplex high-speed bearer channels. In the upstream (customer-to-provider)
transmissions, only low-speed bearer channels are provided.
|
|
logical interface
|
Virtual interface that you create on a physical interface to identify
its connection. Creating multiple logical interfaces allows you to associate
multiple virtual circuits, data line connections, or virtual LANs (VLANs)
with a single interface device.
|
|
Maximum Transmission Unit (MTU)
|
Maximum or largest segment size that a network can transmit.
|
|
Multilink Frame Relay (MLFR)
|
Protocol that allows multiple frame relay links to be aggregated using
inverse multiplexing. It is often used in conjunction with MLPPP.
|
|
Multilink Point-to-Point Protocol (MLPPP)
|
Protocol that allows you to bundle multiple PPP links into a single
logical unit. It can be used to better utilize bandwidth and also has the
advantages of reduced latency and improved fault tolerance.
|
|
Physical Interface Module (PIM)
|
Network interface card that is fixed or can be interchangeably installed
on a Services Router to provide the physical connections to a LAN or WAN,
receiving incoming packets and transmitting outgoing packets. A PIM contains one of
the following interfaces or sets of interfaces:
- Two Fast Ethernet LAN interfaces
- Two T1 or two E1 WAN interfaces
- Single T3 (DS3) WAN interface (J6300 model only)
- ADSL WAN interface (optional) either Annex A to support DSL over
POTS or Annex B which supports DSL over ISDN. (J4300 and J6300)
- Two serial interfaces
|
|
Point-to-Point Protocol (PPP)
|
Link-layer protocol that provides multiprotocol encapsulation. PPP is
used for link-layer and network-layer configuration.
|
|
serial interface
|
Physical LAN interface for transmitting data between computing devices.
A Services Router has two types of serial interfaces:
|
|
T1 interface
|
Physical WAN interface for transmitting digital signals in the T-carrier
system used in the United States, Japan, and Canada. The T1 signal format
carries 24 pulse code modulation (PCM) signals using time-division multiplexing
(TDM) at an overall rate of 1.544 Mbps.
|
|
T3 interface
|
Physical WAN interface for transmitting digital signals in the T-carrier
system used in the United States, Japan, and Canada. T3 signals are formatted
like T1 signals, but carry information at the higher rate of 44.736 Mbps.
T3 is also called DS3.
|